Silver images in light-sensitive print-forming layers



Oct. 8, 1968 P. B. GILMAN, JR.. ET AL 3,404,980

SILVER IMAGES IN LIGHT-SENSITIVE PRINT-FORMING LAYERS Filed Dec. 13, 1962 Fig-.1.

14 S UPPORT EMULSION LAYER SILVER HALIDE SOLVENT AND DEVELOPING AGENT POSED PRINT FORMING LAYER n IZED NUCLEI SILVER IMAGE SUPPORT F 2A 17 BRUSH SILVER NITRATE SOLUTION ;g-.;. ExPosEo PRINT FORMING LAYER I \SENSITIZED NUCLEI SUPPORT E9213 5; /DEVELOPIN6 SOLUTION EXPOSED PRINT FORMING LAYER 4:5 =21; ssusmz ED NUCLEI CSILVER PRINT IMAGE 16 \SUPPORT DEVELOPING SOLUTION u/ER COMPLEXING compouuo EXPOSED PRINT FORMING LAYER SENSITIZ ED NUCLEI SILVER IMAGE UPPORT Paul B. G ilman/ Charles Afiof'f'e IN V EN TORY United States Patent 1 3,404,980 SILVER IMAGES IN LIGHT-SENSITIVE PRINT-FORMING LAYERS Rochester, *N.Y.", assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey Filed Dec. 13, 1962, Ser. No. 244,456 26 Claims. (Cl. 96-27) ABSTRACT OF THE DISCLOSURE 7, Photographic elements and processes feature a photoreactive composition adsorbed to non-silver halide, light insensitive physical development nuclei. The photoreactive composition inhibits physical development of the nuclei until exposure to light destroys the inhibiting effect. Subsequent to exposure, the element is physically developed to produce a negative of the original.

This invention relates to light-sensitive photographic materials and in particular to materials which form a latent image comprising particulate centers of nuclei capable of physical development to a visible silver or other metallic image.

Itis well known in certain photographic systems such as diffusion transfer, to employ disperse particulate matter (often referred to as nuclei or fogging agents) as centers for physical development. These nuclei, however, are not themselves involved in the but merely offer convenient centers for a kind of electrolytic'plating out of metal ions. The nuclei are under the control of a developing or developed image generated independently, for example, by exposure of a silver halide gelatin photographic emulsion in the same or a juxtaposed layer. Such silver halide emulsions are usually opaque, relatively thick, and can be chemically developed. However, high image resolution in processes of this type, has been difficult to obtain since lateral diffusion of solubilized silver halide usually occurs during transfer to the receiving layer from unexposed areas of a developed light-sensitive contacting emulsion layer.

We have discovered light-sensitive elements which may be very thin, transparent, and unaffected by chemical development whichuprovide improved resolution. Lightsensitive precursors for physical development centers are employed, which centers or nuclei are not light sensitive in themselves, and the image is produced by physical development.

One object of our invention is to provide a light-sensitive material capable of producing silver or other metallic photographic image in the exposed regions by physical development.

Another object is to sensitize nuclei which are insensitive to light so that they become physically developable after exposure to light.

An additional object is to provide a light-sensitive material which is inert to conventional chemical development.

A further object is to provide a material in which the mass and optical density of the light-sensitive ingredient is exceedingly small compared to the mass and optical density of the resulting photographic image.

Another object is to provide light-sensitive or photoreactive elements which can function as silver receiving layers after exposure. A further object is to provide processes for silver development of said light-sensitive layers after exposure. Other objects will be evident from this specification and the claims which follow.

We have accomplished these objects by preparing sensi- 'formation of the latent image,

light form excellent centers for physical development. These physical development centers can be formed in a number of ways. In one embodiment of our invention, we may use the well-known nucleating agents for diffusion transfer processes such as particles of silver, metal sulfides, metal selenides, silver proteinate, etc.

Such nucleating agents are used with sensitizing agents which strongly inhibit their activity as development centers. In this case, the sensitizing agent is a type which act as inhibitors only until it is exposed to light. The action of light destroys the inhibiting action so that the nuclei may act as centers for physical development in proportion to the amount of exposure. Various agents may be added to facilitate the photodestruction of the inhibiting action. When nuclei thus sensitized are exposed and physically developed, an image is obtained.

In another embodiment of our invention we may use compounds such as zinc oxide, zinc hydroxide, or lead iodide which react with another type of sensitizer on exposure to light to form nucleating centers for physical development. This type of sensitizer does not inhibit physical development but reacts with the nuclei precursor on exposure to light to form a physically developable species.

The development centers formed by exposure can be physically developed in -a number of ways, for example, by treating with a soluble silver compound such as an aqueous silver nitrate solution followed by immersion in a photographic developing solution, or with a silver halide emulsion layer in the presence of a solution containing a silver halide solvent and a silver halide developing agent, or by incorporating a silver compound complex in the nuclei layer and treating the layer after exposure with a solution containing a silver halide developing agent.

By reference to the accompanying drawing, methods by which light-sensitive layers of the invention can be developed will be apparent, for example.

FIG. 1 shows development by contact with an unexposed emulsion layer in the presence of a silver halide solvent and silver halide developing agent.

FIG. 2A shows development by treating with an AgNO solution followed by treatment in a silver halide developer solution, FIG. 23.

FIG. 3 shows development by treatment with a silver halide developer solution when a silver complex compound has been incorporated in the exposed print-forming layer.

In particular, FIG. 1 shows a support 10 having a printforming layer coated thereon'comprising a light-sensitive nuclei composition 11 contained in a binder 12 wherein after exposure the layer is contacted with an emulsion layer 13 on a support 14 in the presence of a solution 15 containing a silver halide solvent and silver halide developing agent. By the process a silver print 16 is produced in the exposed layer corresponding to the light-exposed portions of said layer.

FIG. 2 shows a method of development comprising brushing a light-sensitive layer of the invention after exposure with a brush 17 containing a silver nitrate solution 18 so that upon treatment of the layer with a developing solution 19, a silver image 16 is produced in said layer.

FIG. 3 shows development of an exposed layer in which a light-sensitive nuclei composition 12 and a silver complex-compound 20 are contained in a binder 11 on a support 10 whereby a silver image 16 is produced in said layer, by treatment with a silver halide developing solution 19.

Various methods within the scope of our invention may be used for rendering the nuclei light-sensitive. The type of sensitizer which does not inhibit physical development but renders nuclei light-sensitive is illustrated by the use of a sulfur containing agent such as hydrogen sulfide, thioacetamide, thiooxamide, or the like, with nucleating agents such as colloidal lead iodide, zinc hydroxide, etc.

3 Y In addition dyes may be used such as rose bengal, eosin, erythrosin, etc.

It will be appreciated that some of the sensitizing agents will perform much better than others and will sensitize certain nuclei to give products which are faster or have higher resolving power than when used with other nuclei. Moreover, a combination of sensitizing agents may be used in order to improve speed or resolving power and, in some instances, to obtain a synergistic effect.

Sulfur compounds for sensitizing the inorganic compounds of the invention comprise a wide variety of sulfur donor materials. Normally, sensitizing of the present inorganic compounds can be brought about by merely mixing the sulfur donor in the liquid coating composition prior to coating on a support. In other cases where a gas is employed, such as hydrogen sulfide gas, the inorganic compound incorporating layers of the invention can be fumed in an appropriate manner. Suitable compounds for sensitizing the inorganic compounds of the invention include the following:

TABLE I Name of Compound Structure sensitizing Ability 1 Dithinnmmido H NCSCSNH; 4 i i 1,4-diphospha-2,3-dithia-1,l,4,4-tctramethoxy-1,4-butanedithione. (C11 0) gP S S P (O C H3) 3 4 i O ,O-diethyl-S-methyl-phosphorothiolothionate (C H O) -1 S 0 H 3 Thioace CH CSNH 5 C H GHOHCH OH 1,2-dihydroxy,3-n1ercapt0propyl,S-oligoethylcnesulfideA-oligo- S 2 hydroxymethyleneoxide-8.

(OH;CH;S)4(CHCHO) SE C H2 0 H L-cystlne S CH2CH(NH2) CO OH; 4

S CH2CH(NH2) C O OH;

3,9-dithla-1,l -nonadecaned HO (OH?) S (CH2)5S (CHmOH 3 Tetramethylene-bis(methylsulfone) CHQSO2 GH2) 4SO2CH3 2 Di-isopropyl su1fox1de (CHQ OHSO CH(CH )1 3 Di .1 1 mlfidn CoH12- CaH1s 2 5-bromo-l-pentyl thioacotate B1'(C Hz) 800 CH 4 3-chloro-1-propyl thioacetate C1(CH)5SCO CH; 4 Evan acid 305-- HOOCCH2SCH(COOH)CH2COOII 3 S Thioglyceraldehy OH GHr-OH 5 HO-CH2 i011 H N NH; Bls(2-isothruron1umethy1) amlnodichlorlde H01. C S (OH?) 1NH(C H2) 5 0 201-1101 2 HzN N H2 1 3,8-dithiadecane 1,10 bis (N-mcthylpipcridinium) p-toluene N (OH is (CH1) 4S (CH2) 2N ZpTS- 2 sulionate. I l

C H; 0 Ha L-eystelne (free base) HSCI-I;CH(NH) 00011 2 CH(CH SH) C ONHCHzC O OH Glutathione. EN 2 C 0 (CH2) 2(NHz) CH0 0 OH 2-mercaptoethyl amine H01- HSCH CH -NH -HCI 2 Cysterne HG] HSGHzCHNHgCOOI-I-HCI 2 Thlodlpropriome d HO O CCH CH SCHzCH OOOH 2 0 Calcium thioglycolate. 4 v I Ca-3Hz0 Z-hydroxyethyl isothiuronium trichloroacctate I{0-CHgCIIg-S-C 01 C C O O 4 NIIQ /C II; S-mcthyl tctrahydro thiapyrau perchlorate s ClOr 2 bitlnoannuehde 1IS Sll 3 TABLE I-Cnti11ued Name of Compound Structure sensitizing Ability 1 Sulfamic acid NHPSOQH 2 Mercapto acetic acid- HSCH COOH 3 Ethyl xanthic acid potassium salt C2H5OUSS'K+ 4 Sodium dithionate Na2S2O4 5 3-mercapto-L2-propane diol H0 CHCHOHCHzSH 4 Sodium sulfide NazS 5 fi-dithiocarbamyl propionic acid- H NCS(CHz)zC0OH 5 B-mercaptoproprionic acid HSCHZCH2COOH 2 m 4,4-dithiodimorpholine [O N S e 5 2 Thioiormanilide CeH NHC S H p 4 Bunorpholinoethyl-thioacctate O N-( 0 Hz) 2 S C O C H; p 3

Ethylene dithiocyanate N O S (CH2); S ON 3 Ammonium sulfamate NH4S OQNHZ 3 5,5-thiodisalicylic acid [HO CSHgC O OHhS 4 2,5-dithiobiurea NI'I2C S NHNHU S NH; 2

None=0; Best=5.

The concentration of the sulfur donor compound of the invention in the photoreactive layer can vary widely. Normally, the effective concentration was found to be quite dependent on the type of donor used with the more labile sulfur compounds being more effective at lower levels than other compounds with less labile sulfur. A suitable range for the sulfide donors of the invention was found to be from about 0.005 gram to about 0.5 gram per liter of the coating melt. A preferred range was found to be from about 0.1 gram to about 0.2 gram per liter of the coating melt.

We have found that when nuclei, such as Carey-Lea silver, colloidal nickel sulfide, or silver proteinate are used, that they can be preferably sensitized by coating the nuclei with a photobleachable dye, such as 1',3-diethylthia- 2'-cyanine iodide. Exposure of the coated silver bleaches the dye and removes its restraining action in the exposed areas. Physical development results in a negative image.

Other compounds which can be used are as follows:

The Carey-Lea type colloidal silver in our preferred embodiment has a mean size of about 140 A. and a mean specific surface of about 3.8x sq. cm./ g. However, the true status of the surface of this colloidal silver has not been determined.

In another embodiment of our invention a colloid layer incorporating physical development nuclei and a sensitizing dye is further sensitized by incorporating an c d-unsaturated monomer, such as acrylamide and a physical development restrainer like 5 mercapto-l-phenyltetrazole.

The a,/3-unsaturated monomer can be varied widely since all that is needed is a receptive double bond. The sulfurcontaining compounds which have been found to be operative in this system are as follows:

( 1) 7,13-dithianonadecane-1,19-bispyridinium-p-toluene sulfonate (2) 3-mercapto1,2,4-triazole (3) l-octyl- 1,2,3,6-tetrahydro- 1,3,5 -triazine-4-thiol The exact reaction between the mercaptans and a,/3- unsaturated compounds is 'not completely understood, but it may be that there is a photo-activated reaction of the mercapto group to the double bond of the a,,8-unsaturated compound prior to, or after, polymerization so that the mercapto group is masked and no longer able to affect physical development.

Unsaturated compounds which have been found to be operative in this system include:

(1) Cellosolve acrylate (2) Dimethylaminoethyl methacrylate (3) Phenyl butynol (4) 2,3-dibromo-2-butene-1,4-diol (5) 2-butene-1-ol (10% in water) (6) S-butenenitride (7) 2-propyne-1-ol (10% in water) (8) 2-methyl-3-butyne-2-ol (10% in water) (9) Ethylene dicyclohexanol (l0) 2,3-butyne-1,4-diol (11) Acrylamide Unsaturated organic molecules which are more reactive than those above which do not react with the mercaptan until a coating is exposed to light may be stabilized by incorporating them in an emulsion copolymer. Copolymers of acrylic acid and 2 other monomers copolymerized in the presence of gelatin have been found particularly effective. Representative compositions are the following.

7 Copolymer (25): Percent solids MaVcC(Gel) 3004 23.3 PVcC(Gel) 3004 23.1 BVcC(Gel) 3004 22.9 EcVcC(Gel) 3004 22.8 MaVcC(Gel) 9008 21.5 MaVcC(Gel) The shorthand representation of the above copolymers may be explained as follows:

Ma methyl acrylate Vc=vinylidene chloride C=acrylic acid P =ethyl acrylate B=butyl acrylate Ec=2 chloroethyl acrylate MaVcC(Gel)-l508 (25) indicates that 25 g. of gelatin are present for every 100 grams of total monomers.

Eight percent of the monomers by weight is acrylic acid.

Fifteen percent of the remaining monomers is methyl acrylate.

The remainder of the monomers is vinylidene chloride.

The main advantage of this source of unsaturate is the superior coating stability of the available acrylic acid. The exact reason for the stability of the acrylic acid is not known but is believed due in part to the association of the acrylic acid with the gelatin present so that when the copolymerization of the methyl acrylate, vinylidene chloride and acrylic acid takes place a packet of copolymer is formed around globules of gelatin with co-absorbed acrylic acid or vice versa, with globules of copolymer surrounded by a coating of gelatin with co-absorbed acrylic acids.

Another class of compounds which is within the scope of our invention is that which does not physically restrain the physical development of nuclei but instead increase the apparent activity of the nuclei after they have been exposed to light. Typical of this class of compounds are the sensitizing dyes used with silver halide emulsions such as Rose Bengal, Eosin blue, Eosin yellow, tetraiodofluorescein, methylene blue, etc. These dyes are particularly useful for incorporation with the above nae-unsaturated compound containing layers.

In preparing the light-sensitive elements, one of the nucleating agents referred to above is dispersed in a suitable binder and then the mixture coated on a support using any of the known coating methods. Supporting materials can be any of the known materials for this purpose, such as film base (e.g., cellulose nitrate film, cellulose ester film, etc.), plastic supports (e.g., polyethylene, polyethylene terephthalate, etc.), paper, metal, glass, and the like.

Suitable binders for incorporating the present inorganic compounds can include any of the water-permeable matrials, such as gelatin or other hydrophilic materials, such as collodion, albumin, cellulose derivatives, certain synthetic resins, (polyvinyl alcohol), and the like,

Sensitizing as used herein refers to the treatment of the inorganic compounds in the print-forming layer with compounds referred to above so that improved sensitivity of such layers to lower light levels is obtained as well as a sensitivity in some cases to a broader region of the spectrum. Sensitizing of the inorganic compounds has also been found to give improved duration of the latent image produced by exposure of the print-forming layers to light, thus not requiring substantially immediate development of such layers.

The sulfur-containing compounds of the above disclosure can be employed in a number of ways. For example, with hydrogen sulfide, the print-forming layers can be fumed with H 8 gas. In other cases, the compounds can be incorporated in the sensitive layer in conjunction with the inorganic compounds in the invention.

In preparing light-sensitive print-forming layers the particular inorganic compound in question is formed and then after suitable washing, a slurry of the compound is dispersed in a binder, such as gelatin, in preparation for coating on a support.

For example, zinc nitrate in water would be mixed with sodium hydroxide and after precipitation of Zinc hydroxide and suitable washing of the slurry to remove unwanted components of the reaction, a water slurry of the precipitate would be mixed with a suitable binder and coated on a support. The sulfur-containing sensitizing compound can be added to the final binder-precipitate mixture and after adequate stirring the mixture would be ready for coating on a support.

The wet thickness of such coatings can be in the range from about 0.001 to about 0.01 inch with a preferred wet thickness in the range from about 0.003 to about 0.006 inch. Thicker coatings can also be employed without detracting from the invention.

Although the various components of light-sensitive compositions of the invention can vary over a wide range, it has been found that quite useful compositions are prepared where the binder is present in the range from about 2 percent to about 20 percent by weight of the total coating melt; where the inorganic compounds are present in the range from about 2 percent to about 20 percent by weight of the total coating melt.

Light-sensitive coatings of this invention can also be spectrally sensitized with particular dyes in which case the coatings would become more sensitive to a particular wavelength of the spectrum. For example, certain dyes such as Eosin and erythrosin spectrally sensitize coatings of lead iodide, zinc oxide, zinc hydroxide, or the like, whether or not the coating had been previously sensitized with a sulfur-containing sensitizing compound. Spectral sensitization is preferably accomplished by having the dye present during the time of precipitation of the particular inorganic compound of the invention.

In one mehtod of practice of the invention, a print is formed in a light-sensitive layer of the invention by (1) exposing said layer to an actinic light source from behind an imagewise transparency having opaque areas, and (2) developing said layer after exposure by contacting with an unexposed silver halide emulsion layer in the presence of a silver halide solvent and silver halide developing agent. After a brief contacting period of, say, about 30 seconds, the layers can be separated showing a silver image in the exposed light-sensitive layer corresponding to the exposed portions thereof and showing a reverse image in the contacting emulsion layer.

Another manner in which the latent image in exposed light-sensitive layers of the invention can be developed comprises swabbing with an aqueous silver solution such as a dilute silver nitrate solution and then immersing the swabbed layer in a photographic developing solution followed by washing the developed print with Water to stabilize it. Other methods for development of exposed layers of the invention comprise incorporating in said layers a silver complexing compound, such as silver-thicsulfate complex or the silver salt of 4,5-(2,3D fructopyrano)-2-oxazolinolidinethione, and the like. In processes where a silver complexing agent is incorporated in the sensitive layer, such layers are normally developed by treatment with a conventional silver halide developing solution.

Actinic light exposing sources can be any suitable tungsten source such as a Kodak No. 2 Photoflood Lamp, electrically heated incandescent filaments, and the like.

In developing the exposed layers of the invention, any of the usual developing agents can be used such as N- monomethyl p aminophenol sulfate; dihydroxybenzene; hydroquinone; certain hydroquinone compounds (e.g., chlorohydroquinone, dichlorohydroquinone, bromohydroquinone, etc.); 1-phenyl-3-pyrazolidone and its derivatives; triaminophenols; and the like.

Silver halide solvents for use in the developing process of the invention include alkali metal thiosulfates, ammonium thiosulfate, alkali metal thiocyanate, ammonium thiocyanate, sodium sulfite, etc.

Silver halide emulsions useful in developing the exposed sensitive layers of the invention can comprise any of the conventional gelatino silver halide developing-out emulsions, e.g., gelatino silver chloride, -chlorobromide, -chloroiodide, -chlorobromoiodide, -bromide, and bromoiodide developing-out emulsions. The emulsions for use in the invention include emulsions having a silver halide carrier other than gelatin, for example, collodion, al-

bumin, synthetic resins, and the like. These emulsions can be coated in the usual manner on a suitable support, e.g., glass, cellulose nitrate film, cellulose ester film, paper, or metal, etc. The emulsions of the invention can contain sensitizers or other addenda for improving the character of the emulsion as is well known in the art. The silver halide emulsions useful in the process of the invention can be prepared according to known methods such as those described in Hewitson and McClintock, US. Patent 2,618,556, issued Nov. 18, 1952, for example.

The invention will now be further illustrated by way of the following examples.

Example 1 A light-sensitive layer of the invention was prepared as follows:

150 g. of zinc nitrate was dissolved in 1500 ml. of methanol at 40 C. 40 g. of sodium hydroxide dissolved in 400 ml. of distilled water was added to the zinc nitrate solution over a l5-second interval to form a precipitate of zinc hydroxide which settled to the bottom of the container. Clear supernatant liquid was poured 01f and the precipitate was redispersed in distilled water; and, after allowing the zinc hydroxide precipitate to settle again, the distilled liquid was poured off. The layer was then prepared by mixing 2.5 g. of zinc hydroxide precipitate dispersed in 25 ml. of distilled water with 100 ml. of a 5 percent gelatin solution. The solution was then pumped through a hand homogenizer and 4 ml. of a 7% percent aqueous saponin solution and 3 ml. of a 10 percent formaldehyde solution were then added to the homogenized solution with suitable agitation. The mixture was then coated on a titanium dioxide pigmented cellulose acetate support.

The coating was then dried and fumed with gaseous H 8 under low light illumination such as under red safelight conditions. After fuming, the coating was then exposed to a Kodak No. 2 Photoflood Lamp at a distance of 20 inches for 4 seconds from behind a negative image transparency. The exposed layer was then physically developed by using it as a receiver for the diffusion transfer of silver from an unexposed fine-grain, negative-speed bromoiodide emulsion such as a Kodak Panatomic-X Negative Film. The emulsion layer was soaked in a solutionof the composition of Table 2 for about 5 seconds prior to contacting with the receiving layer. After a second contacting interval, the two layers were separated to show an imagewise deposit of silver in the areas of the zinc hydroxide incorporating layer which had received the exposure.

Water to 1 liter.

Zinc hydroxide of improved photographic characteristics for use in the zinc hydroxide sensitive coatings was obtained where the zinc hydroxide was precipitated in a portion of alcohol or where at least two or three washings of the precipitate was carried out before dispersing the coating melt.

Example 2 Zinc hydroxide for use in the present example was prepared by precipitating as in Example 1. To coating melts using this precipitate was added silver compounds as follows for nucleation and development of said layers after exposure.

Sanzlple A.Silver thiosulfate Dissolve 7.25 g. of silver nitrate in 100 ml. of distilled water and add the solution to 100 ,ml. of a 2.5 percent sodium chloride solution with stirring. Wash the silver chloride precipitate by a decantation method and add the slurry to ml. of distilled water containing 25 g. of sodium thiosulfate and make up to ml. total volume.

10 ml. of the silver-thiosulfate complex was then added to 100 ml. of a 5 percent gelatin solution containing 10 g. of aqueous zinc hydroxide slurry of Example 1. The mixture, after thorough stirring, was coated on a paper support.

Sample B.Silver nitrate A coating similar to Sample A was made except that 5 ml. of a 6 percent silver nitrate solution replaced the silver thiosulfate complex. Coatings in a similar ,manner were made on a paper support.

Sample C.Silver salt of 4,5 (2,3D-fruclopyran0)-2- oxazolidinethione A coating similar to Sample A was made except that a silver complex of the above thione compound replaced the silver-thiosulfate complex. The silver-thione complex was prepared by adding 1.1 g. of the thione compound to a silver nitrate solution containing 0.84 g. of silver nitrate. The silver-thione complex was then added to a 5 percent gelatin solution containing 10 g. of aqueous zinc hydroxide slurry of Example 1 per 100 ml. total volume at a level to give m1. total volume. The coating melt was then coated on a paper support.

The elements of each of the samples were then exposed as in Example 1 and developed by contacting the exposed receiving layer with a developer having the following composition in Table 3.

Water to 1 liter. "Final pH at 75 F.=l0.3

By the development step, silver images of good resolution were obtained in each of the layers.

Example 3 To 50 g. of a percent gelatin solution was added 5 g. of XX78 French processed zinc oxide purchased from the New Jersey Zinc Company and the mixture was pumped through a hand operated homogenizer. To the mixture was added 2 ml. of a 7 /2 percent saponin solution and 1% ml. of a percent formaldehyde solution The preparation was then coated at 0.003 inch wet thickness on a titanium dioxide pigmented cellulose acetate support. After drying, the above coating was fumed with gaseous H 8 for 5 seconds exposed to line negative for 4 seconds using the illumination of a Kodak No. 2 Photoflood Lamp at a distance of inches. The exposed coating was then developed by contacting said coating with a layer of finegrain, negative-speed bromoiodide emulsion after immersing in a developer of the composition of Table 2 for 2 seconds. After the emulsion layer was suitably soaked with the developer composition, it was rolled in contact with the exposed znc oxide layer. After a 30-second contacting interval, the two elements were separated showing a good silver image produced by physical development in the exposed zinc oxide layer. The silver image was obtained in the areas corresponding to the exposed areas of the layer.

Exposure of similar print-forming layers using other imaged materials, such as positive, continuous-tone prints, showed similar results using zinc oxide incorporating layers, for example.

Example 4 To separate containers having 100 ml. of a 5 percent gelatin solution containing 6 g. of zinc hydroxide precipitates prepared according to Example 1, was added the following.

Container No. 1no additions Container No. 2-0.1 gram per liter of thioacetamide Container No. 30.1 gram per liter of dithiooxamide A stock solution of Carey-Lea silver was made to con tain 0.5 ml. of Carey-Lea silver (25.2 g. silver per kilo and 55.5 g. gel per kilo) in 100 ml. of 2% bone gelatin.

To 85 ml. of 2% bone gelatin was added 2 ml. of the above solution, 4 ml. of 7 /2 saponin, and 2 ml. of 10% formaldehyde. This mixture was then coated on film support at a wet thickness of 0.002 inch thickness.

The coating was soaked for 1 minute in a solution containing 20 mg. of 1,1-diethyl-2,2-cyanine iodide in 1 liter of ethyl alcohol. The coating was dried, then exposed through a negative test object to a No. 2 photoflood lamp for 15 seconds at a distance of 6 inches. The exposed coating was used as the receiver for the diffusion transfer of of silver from an unexposed silver halide coating. The emulsion used was a gelatino silver bromochloride lightsensitive emulsion and the developer was of the following composition:

Sodium sulfite, desiccated "grams" 23.0 Potassium sulfite do 23.0 N-methyl-p-aminophenol sulfate do 6.0 Sodium thiosulfate-5H O do 7.7 Sodium metaborate-8H O do 46.0 Hydroquinone do 2 15.0 15 M ammonium hydroxide ml 10.0

12 23.2% methylnaphthalene sodium sulfonate ml 3.5 Water ml 1000.0

After a 30-second contact time, the two layers were stripped apart to reveal a positive silver print in the Carey-Lea silver coating.

Example 6 DEVELOPER Silver-ion concentration 4 10 M; pH 12.0; temp. 25 C.

Solution A:

Deaerated distilled water ml 800.00 CD-3 Developing Agent, [4 amino 3- methyl N ethyl N ([B-methylsulfonamido ethyl)aniline sesquisulfate monohydrate] grams 2.25 Tribasic potassium phosphate grams 50.00 Grams dissolved in Solution B: 50 ml. distilled water Potassium chloride 0.61 Silver nitrate 0.61

The AgCl is precipitated and allowed to stand in a dark bottle. The supernatant liquid is decanted and the precipitate dissolved in a solution of 6.20 grams of sodium thiosulfate pentahydrate dissolved in ml. of distilled water.

Solutions A and B were mixed and diluted to a final volume of 1000 ml. 6 N sulfuric acid was used to adjust the pH to 12.00.

DEVELOPER Silver-ion concentration 1X10 M; pH 11.0; temp. 25 C.

Solution A:

Deaerated distilled water ml 800 Elon developing agent g 0.444 Hydroquinone g 0.284 Dibasic potassium phosphate g 50.0

Solution B:

Same as for Solution B of the previous developer in this example except that a solution of 10.50 g. of sodium thiosulfate pentahydrate in 100 ml. of distilled water was used to dissolve the AgCl.

To 100 ml. of 10% bone gelatin add:

(1) 100 ml. distilled water (2) 5 ml. of a silver protein solution [made by adding 1.0 g. of silver protein (Mallinckrodt) to 1 liter of 2% gelatin} l 3 (3) ml. of a 7 /2 aqueous saponin solution (4) 3 ml. of a aqueous formaldehyde solution To separate ml. portions of the above mixture were added 0.1 ml. of the following 1% dye solutions:

(a) Rose Bengal (b) Eosin yellow (c) Eosin blue (d) Tetraiodofluorescein The coatings were made .003 inch wet thickness on pigmented cellulose acetate support, then exposed 15 seconds to a reflector flood lamp at a distance of one foot through a step wedge and a line image. The exposed layer was then used as the receiver for the diffusion transfer of silver from an unexposed layer of Panatomic-X which had been dipped in a developer of the following composition:

Sodium sulfite desiccated g 23.0 Potassium sulfite g 23.0 N-methyl-p-aminophenol sulfate g 6.0 Sodium thiosulfate- 5 H O g 7.7 Sodium metaborate-S H O g 46.0 Hydroquinone g 15.0 15 M ammonium hydroxide ml 10.0 23.2% rnethylnaphthalene sodium sulfonate ml 3.5 Water m 1000 gelatin, exposure to light, followed by physical development, produced no images with the exception of the methylene blue-gelatin coating which produced a very low density silver image after physical development.

Example 8 A special method of preparing nickel sulfide nuclei produces images of higher quality than those produced by commonly known methods of preparing such nuclei. The improvement in picture quality is evidenced by both a higher maximum density and a longer scale. In addition, these nickel sulfide nuclei dispersions exhibit greater stability in the liquid state and do not lose their ability to give prints with higher Dmax. The quality of images is greatly affected by a large number of variables. To obtain the best results, a critical balance of a number of conditions appears to be necessary. The following nickel sulfide nuclei preparations under the particular conditions described yield the advantages noted above.

The best results are obtained by preparing 0.01 mole of Na S in three to eight liters of solution and adding the soluble nickel salt to the soluble sulfide over a period of less than thirty seconds and forming the NiS in the presence of gelatin.

Preparation of nickel sulfide nuclei.-Precipz'iation vessel Solution B Nickelous nitrate (1.0 N) cc 20.8 H O cc.... 535

Precipitatiom-Add Solution A to the precipitation vessel at 104 F. five seconds before adding Solution B. Solution B is then dumped into the kettle over a period of ten seconds with rapid mechanical agitation. At the end of the dump, the nuclei are stirred for thirty seconds at 104 F. Four hundred fifty (450) grams of a 10% gelatin solution were added and the nuclei stirred at 104 F. for an additional fifteen minutes.

Receiving sheet.A dispersion was prepared with 500 gm. of the above nuclei, 400 gm. of a 10% gelatin solution, and 1600 cc. distilled water. To this dispersion, while stirring at 104 F., were added tone modifiers of the type described in Gilman, Jones and Rasch U.S. Ser. No. 141,036, filed Sept. 27, 1961. To this was added 240 cc. of a 15.3% saponin solution as a coating aid and cc. of a 10% formaldehyde solution as a hardener. The dispersion was then coated on white pigmented cellulose acetate at a coverage to yield 82.5 mg. gel/square foot.

Negative emulsion c0ating.A silver bromoiodide emulsion was coated on a white pigmented cellulose acetate support at a coverage to yield 59.3 mg. silver and 550 mg. gel/ square foot. A gelatin overcoat was applied over this layer at a coverage to yield 146 mg. gel/sq. ft.

Devel0per.As described in Table 2, Example 1.

Pr0cess.After exposure the negative was soaked in the developer solution for approximately six seconds then immediately brought in contact with the receiver sheet. After two minutes, the two layers were separated to yield a high-quality continuous-tone black-and-white print on the receiver sheet.

These nuclei also give improved results when used in the diffusion transfer system.

Example 9 To ml. of 2% bone gelatin is added:

To 10 ml. of the mixture described above was added:

5 ml. of 10% photographic bone gelatin 2 m1. of a 50% ethyl alcohol solution of acrylamide 0.1 ml. of a 1% Rose Bengal solution 0.4 ml. of a 1% S-mercapto-l-phenyl-tetrazole The mixture was then'coated .002 inch wet thickness on cellulose acetate film support.

The dried coating was exposed 20 seconds through a 0.3 log E step tablet to a reflector flood lamp at a distance of one foot. After physical development, a dark silver deposit was produced in the exposed areas with 6 visible steps occurring on the processed layer indicating the threshold response to be approximately a 0.6 second exposure. The physical development was accomplished by immersing a layer of unexposed silver halide emulsion in the developer of Example 7 for approximately 3 seconds then rolling it in contact with the exposed nuclei layer. Contact times before stripping apart of from 30 seconds to 2 minutes produced good images.

Example 10 Nickel sulfide nuclei prepared and coated in the dark with a sensitizing dye were found to form a negative image after exposure and physical development.

To 25 cc. of a nickel sulfide preparation as described '11 Example 8 were added:

1.2 cc. of a 7.5% saponin solution Tone modifiers of the type described in Gilman, Jones and Rasch, U.S. Ser. No. 141,036, filed Sept. 27, 1961.

15 0.9 cc. of a 10% formaldehyde solution .17 mg. of 3,3-diethyl-9-methylthiacarbocyanine bromide Water to bring the .volume to 30 cc.

Hand coatings weremade at-.006"' wet thickness on white pigmented cellulose acetate support. These were dried rapidly with forced air at 15 and 55 RH. A piece of the coating was exposed to a graded light intensity from a No. 2 photoflood lamp at 2 feet for 10 seconds, A gelatino silver bromochloride photographic sheet was soaked approximately 6 seconds in the developer solution described in Table 2.

After soaking, it was immediately brought into contact with the exposed dye-nickel sulfide coating. After two minutes the layers were separated revealing a silver image on the dye-nickel sulfide-nuclei layer in the areas of exposure.

Example 11 Imagewise conversion of white zinc sulfide to black silver sulfide may be controlled by the imagewise destruction of -mercapto-l-phenyl tetrazole.

To 100 ml. of a'zinc sulfide dispersion containing 36.36 mg. ZnS in a 2% solution was added:

4.0 ml. of 7 /2% aqueous saponin solution 2.0 ml. of 10% formaldehyde solution To 10 ml. of the above mixture was added:

5.0 ml. of 10% aqueous 2,3-butyne-1,4-diol 2.0 mi. of a 1% methanol solution of 5-mercapt0-l-phenyl tetrazole 0.3 ml. of a 1% aqueous solution of Rose Bengal.

A- coating .004 wet thickness was made on a pigmerited cellulose acetate support.

When the above coating was dried, it was exposed through a line image to a reflector flood lamp for 10 seconds at a distance of 2 feet. The layer was then developed by immersion for 2 seconds in 100 ml. of a 1% silver nitrate solution to which 0.2 ml. of zinc sulfide preparation had been added. In the areas of exposure the white zinc sulfide of the coating was converted to dark brown silver sulfide.

The addition of a very small amount of zinc sulfide nuclei to the silver nitrate was used to obtain the deposition of silver in the exposed areas in a reproducible manner.

This process provides a very simple and short (twosecond) method of processing a light-sensitive layer of contact paper sensitivity in which no fixation of the lightsensitive layer is necessary after development.

Example 12 A light-sensitive layer of the type described in Example 8 which has the unsaturated organic molecules stabilized by their incorporation in an emulsion of a copolymer is as follows:

To 100 ml. of 5% gelatin is added:

(1) 20 ml. of a nickel sulfide preparation, prepared as described in Example 8 (2) 5 ml. of 7 /2% saponin (3) 3 ml. of 10% formaldehyde To 10 ml. of the above mixture add 2 ml. of a gel copolymer consisting of a 22.9 solids mixture of MaVcC Gelatin-1508, as defined in the specification above, 0.1

ml. of 1% Rose Bengal solution and 0.2 ml. of a 1% to two minutes. After the two layers are stripped apart, good silverimages are found deposited in the exposed areas of the nuclei coating.

, Example 13 A light-sensitive layer was prepared as follows:

30 gms. lead nitrate was dissolved in 300 ml. of distilled water 33 gms. potassium iodide was dissolved in 330 ml. of distilled water The solution of the potassium iodide was added to the lead nitrate solution with rapid stirring. After the precipitate settled, it was washed by decantation. 500 m1. of water was added to the washed precipitate to make a slurry to which was added:

ml. of 10% gelatin 3 ml. of 7 /2% saponin 0.5 ml. of 10% formaldehyde 0.5 ml. of 1% thioacetamide This gel solution as prepared above was coated .006" wet thickness on a white pigmented support. After drying, the emulsions were exposed through a line image to a No. 2 photofiood lamp for 10 seconds at a distance of 1 foot.

An image was developed in the exposed areas of the above emulsion by putting it in intimate contact with a gelatino silver bromoehloride photographic sheet which had been soaked for 30 seconds in the developer of Table 2, Example 1. When the layers were separated after 1 minute, there was a silver image developedon the lead iodide layer in the areas of previous exposure.

It is within the scope of our invention to employ integral systems wherein a silver halide layer is coated on the same support with the light-sensitive nuclei layer. For instance, the silver halide could be coated on the support followed by a superimposed black layer, next a white layer, and then a'layer of light-sensitive nuclei. Exposure of the nuclei layer, followed by development employing a silver halide solvent, would result in diffusion of silver halide to the nuclei and physical deveopment of the image. In a similar system the light-sensitive nuclei could be coated directly on a transparent support with a superimposed black stripping layer and a silver halide layer over the stripping layer. Exposure through the transparent support, followed by development employing a silver halide solvent, would result in physical development of the nuclei after which the silver halide layer could be removed along with the black stripping layer.

The light-sensitive nuclei layer of this invention, when normally exposed to a positive image, results ina negative image. However, a reversal system can be employed wherein a positive image will be obtained. After exposure to light of the light-sensitive nuclei, followed by mild physical development, a mild bleach is used to remove the silver. By flashing to light or by similar fogging action, followed by physical development, a positive image is obtained. As an alternative, the fogging action might take place during the bleaching step or during the second physical development step.

In the above application, our examples have been specific to images formed by physical development in which silver is used to form an image. However, other metals are known for use in physical development and could be used for the same purpose as silver by the appropriate substition of metallic salts. Metals which are members of the electromotive scale below hydrogen are those which are most commonly employed for this purpose and include copper, arsenic, antimony, platinum, gold, mercury, silver and the like. The use of these metals to form images is within the scope of this invention. It has not been practical to show an example for each and every one of these metals, but silver images are believed to be those most preferred and to be typical of the physical development within the scope of this invention to obtain a metallic image.

'17 It will be appreciated that the photoreactive elements prepared according to our invention; are prepared under safelight conditions as required.

The invention has beendescribed in detail with -particular reference to preferred embodiments thereof, but it will be understood that variations 'and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

1. A photographic element comprising a support having thereon, non-silver halide, light insensitive, nuclei which are active sites for physical development and a photoreactive composition adsorbed to the nuclei which inhibits physical development of the nuclei until exposure to light destroys the inhibiting effect of said photoreactive composition.

2. A photographic element of claim 1 in which the photoreactive composition is a light sensitive dye.

3. A photographic element of claim 1 in which the nuclei are silver proteinate.

4. A photographic element of claim 1 in which the nuclei are colloidal silver.

5. A photographic element of claim 1 in which the composition is a light sensitive dye selected from the class consisting of anhydro-S-carboxyethyl-Z-(4-p-dirnethylamino phenyl-1,3-butadienyl-l-dimethyl-1H-benz[e]indolium hydroxide monosulfonate, 3,7-bis(4-methoxy-3- sulfobenzamido)dibenzothiophene dioxide Na salt, anhydro 9 methyl-3,3'-di(3-sulfobutyl)thiocarbocyanine hydroxide, 4',4"-disulfo-p-terphenyl, 5- (3-ethyl-2(3 -benzo thiazolylidene) ethylidene] 3-heptyl-l-phenyl-Z-thiohydantoin, 3,3-diethyl-9-methylthiacarbocyanine bromide and 1, l -diethyl-2,2'-cyanine iodide.

6. A photographic element of claim 1 in which the photoreactive composition is a mixture of a sulfur compound which inhibits physical development of the nuclei, an a,,8 compound and a spectral sensitizing dye.

7. A photographic element of claim 1 in which the composition is a mixture of a sulfur compound selected from the class consisting of 7,l3-dithianonadecane-l,l9- bis-pyridinium-p-toluenesulfonate, 3-'mercapto-l,2,4-triazole, l-octyl-l,2,3,6-tetrahydro-1,3,5-triazine-4-thiol, 1- decyl-l,2,3,6-tetrahydrol,3,5-triazine-4-thiol 1-hexyl-l,2, 3,6-tetrahydrohydro-1,3,5-triazine-4-thiol, 1-propyl-1,2,3, 6-tetrahydro-l3,5-triazine-4-thiol, 1-ethyl-l,2,3,6-tetrahydro-l,3,5-triazine-4-thiol, l-cyclohexyl-l,2,3,6-tetrahydro- 1,3,5-triazine-4-thiol, l-mono-sec-butyl-l,2,3,6-tetrahydro- 1,3,5triazine-4 thiol, piperindinylmethyl-2-thio-oxazolidine, Z-mercaptobenzimidazole, 3,9-dithiaundecane-1,11- bis-(N-methylmorpholinium)-p toluene mercapto-S-methyl-l,2,4-triazole, 2-benzoxazole-thiol, l-(3-aminophenyl)- S-mercapto-tetrazole hydrochloride, 1-(3-methy1sulfonamidophenyl) mercapto-tetrazole, 1 (4-capr0ylaminophenyl)-5mercaptotetrazole and l-.(3-acetomidophenyl)- S-mercaptotetrazole adsorbed on the nuclei, an a,,B-unsaturated compound and a spectral sensitizing dye.

8. A photographic element of claim 1 in which the composition is a mixture of a sulfur compound which inhibits physical development of the nuclei, a spectral sensitizing dye and an a,B-unsatu-rated compound selected from the class consisting of cellulose acrylate, dimethylaminoethyl methacrylate, phenyl butynol, 2,3-dibromo-2- butene-l,4-diol, Z-butene-l-ol, Z-butene-nitride, 2-propyne-l-ol, ethylene dicyclohexanol, 2,3-butyne-l,3-diol and an acrylamide.

9. A photographic element of claim 1 comprising silver nucleihaving l',3diethylthia-2-cyanine iodide adsorbed on the nuclei.

10. A photographic element of claim 1 in which the nuclei are silver proteinate and the composition is a light sensitive dye.

11. A photographic element of claim 1 in which the nuclei are colloidal silver and the composition is a light sensitive cyanine dye.

18 .9121 photographic element of claim 1 in which the photoreactive composition is a mixture of a sulfur compound which inhibits physical development of the nuclei, a spectral sensitizing dye and a vinyl monomer.

13. A photographic element of claim 6 in which the sensitizing dye isselected from the class consisting ofRose Bengal, Eosin blue, Eosin yellow, 'tetraiodofluoroescein and methylene'blue. i

14. A process for forming a metallic image in a light sensitive layer comprising non-silver halide, light insensitive nuclei which are active sites for physical development and a photoreactive composition adsorbed to the nuclei which inhibits physical development of the nuclei until exposure to light destroys the inhibiting effect of said photoreactive composition comprising (a) exposing said layer to actinic radiation and (b) contacting said layer with a solution of a metallic compound.

15. A process of claim 14 in which the exposed nuclei are contacted with a solution of a silver compound.

16. A process of claim 14 in which the nuclei are silver proteina-te and the composition is a light sensitive dye.

17. A process of claim 14 in which the nuclei are silver proteinate.

18. A process of claim 14 in which the nuclei are colloidal silver.

19. A process of claim 14 in which the nuclei are colloidal silver and the composition is a light sensitive cyanine dye.

20. A process of claim 14 in which the composition is a light sensitive dye selected from the class consisting of anhydro 3-carboxyethyl-2-(4-p-p-dimethylamino-phenyl- 1,3-butadienyl-1-dimethyl-lH-benz[e]indolium hydroxide monosulfonate, 3,7-bis(4-methoxy-3-sulfobenzamido)dibenzothiophene dioxide Na salt, anhydro-9-methyl-3,3' di-(3-sulfobutyl)thiocarbocyanine hydroxide, 4', 4"-disulfo-p-te-rphenyl, 5-[ (3-ethyl-2 3 -benzothiazolylidene) ethylidene]-3-heptyl-l-phenyl-Z-thiohydantoin and 3,3'-diethyl-9-methylthiacarbocyanine bromide.

21. A process of claim 14 in which the composition is a mixture of a sulfur compound which inhibits physical development of the nuclei, a spectral sensitizing dye and an cap-unsaturated compound.

22. A process of claim 20 in which the composition is a mixture of a sulfur compound and an anti-unsaturated monomer which is stabilized by incorporation in an emulsion copolymer with gelatin.

23. A process of claim 20 in which the nuclei are colloidal silver and in which the composition is a mixture of a sulfur compound and an O S-unsaturated monomer which is stabilized by incorporation in an emulsion copolymer with gelatin.

24. A process of claim 20 in which the sulfur compound is selected from the class consisting of 7,13-dithianonadecane-l,l9-bis-pyridinium-p-toluenes-ulfonate, 3-mercapto-1,2,4-triazole, 1-octyl-l,2,3,6-tetrahydro-1,3,5-triazine- 4-thi0l, l-decyl-1,2,3,6-tetrahydro-1,3,5-triazine-4-thiol, 1- hexyl-l,2,3,6-tetrahydro-1,3,5-triazine-4-thiol, l-propyl- 1,2,3,6-ttetrahydro-1,3,5-triazine-4-thiol, l-ethyl-1,2,3,6- tetrahydro 1,3,5 triazine-4-thiol, 1-cyclohexyl-1,2,3,6- tetrahydro-1,3,5-triazine-4-thiol, l-mono-sec-butyl-1,2,3,6- tetrahydro-l,3,5-triazine-4-thiol, piperdinylmethyl-Z-thiooxazolidine, 2-mercaptobenzimidazole,3,9-dithiaundecane- 1,1l-bis-(N-methylmorpholinium)-ptoluene mercapto-S- methyl-1,2,4-triazole, Z-benzoxazole-thiol, 1-(3-aminophenyl)-5-mercaptotetrazole hydrochloride, 1-(3-methylsulfonamido-phenyl)-5-mercaptotetrazole, 1-(4-caproylaminophenyl)-5-mercapto-tetrazole and 1-(3-acetomidophenyl)-5-mercaptotetrazole adsorbed on the nuclei, an tsp-unsaturated compound and a spectral sensitizing dye.

25. A process of claim 20 in which the t p-unsaturated compound is selected from the class consisting of cellulose acrylate, dimethylaminoethyl methacrylate, phenyl butynol, 2-3-dibromo-2-butene-1,4-diol, 2-butene-1-ol, 2-butenenitride, 2-propyne-1-ol, ethylene dicyclohexanol, 2,3- butyne-l,4diol and an acrylamide.

26. A process of claim 20 in which the dye is selected 19 20 from'the class consisting of Rose Bengal, Eosin blue, .FOREIGN PATENTSv Eosin yellow, tetraiodofluorescein and methylene blue. 201,416 4/1956 Australia V I References Cited 5; UNITED STATES PATENTS 7 2 59 237 12 1954 Land" C: E. VANHORN, Assistant Examiner. 2,882,151 4/1959 Yiltzy et a1 96-29 I 5 NORMAN G. TORCHIN, Primlzry Examiner.

U.S. DEPARTMENT OF COMMERCE PATENT OFFICE Washington, 0.6. 20231 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,404,980 October 8 1969 Paul B. Gilman, Jr. et al.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as show below: Column 3, line 24, "C6H 2 S-'C Hl should read Columr 8, line 55, "mehtod" should read method Column 11, line 22, "znc" should read zinc Column 12 between lines 3 and 4 insert pH l0. 3 line 12, "non should read none Column 13, line 1, "7 1/2" should read 7 1/2% Column 17, line 45, 3,6-tetrahydrohydro-l,3,5triazine4thiol" should read 3,6-tetrahydro-l,3,5triazine4-thiol Column 18, line 31, anhydro-3-carboxyethyl2 (4-pp-dimethylamino-phenylshould read anhydro- 3carboxyethyl2- (4P-dimethylamino-phenyl- Signed and sealed this 14th day of April 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr. WILLIAM E. SCHUYLER,

Attesting Officer Commissioner of Patents 

